Objectives: To evaluate the vitro activity of tigecycline and other antimicrobial agents against epidemiologically well-defined Acinetobacter bloodstream isolates.

Methods: The in vitro activity of tigecycline and 11 other antimicrobial agents was determined for 217 epidemiologically unrelated isolates belonging to the A. calcoaceticus-A. baumannii complex. Isolates were recovered from bloodstream infection in the United States between 1995 and 2002 during a prospective surveillance study (SCOPE). Species identification was confirmed by ARDRA; RAPD-PCR and PFGE patterns were obtained to exclude isolates that were clonally related, i.e. only one isolate per strain type was included. MICs were determined using microbroth dilution. CLSI/NCCLS guidelines were used for interpretation.

Results: MIC50s and MIC90s (mg/L) are depicted in the table.

Resistance rates were lower in Acinetobacter genomic species 3 and 13TU than in A. baumannii strains.

Conclusions: Tigecycline, amicacin, and colistin showed the highest in vitro activity against A. baumannii bloodstream isolates. Our data confirm the high resistance of clinical A. baumannii isolates against betalactams and quinolones but resistance to imipenem and aminoglycosides was less than suggested from surveillance studies that don't control for copy strains associated with endemic or outbreak situations.

Session Details

Date:

19/04/2008

Time:

00:00-00:00

Session name:

18th European Congress of Clinical Microbiology and Infectious Diseases